1. Field of the Invention
The present invention relates to a storage apparatus, a method of detecting a failure in a head of a storage apparatus, and a storage medium storing a failure detection program. And more particularly, to a storage apparatus which is provided with a tunnel effect MR head (TuMR head) as a head to thereby read information from a recording medium such as a magnetic disk, a method of detecting a failure in a head of a storage apparatus, and a storage medium storing a failure detection program.
2. Description of the Related Technology
In a storage apparatus, (for example, an HDD that has recently been used in various types of products such as a desktop PC, notebook PC, server, audio-visual equipment, and automobile product), linear density (BPI)/transfer rate is improved along with improvement in the recording density (surface density). In recent years, various types of magnetic disk heads supporting a higher transfer rate are developed in order to allow the technological update of the storage apparatus and produced on a commercial basis.
As one of the above magnetic disk heads, there is known a TuMR head which is based on tunnel effect (refer to, e.g., Patent Document 1 (Patent Publication WO2002/093564)). A magnetic recording/reproducing apparatus disclosed in this Patent Document 1 has a TuMR head serving as a magnetic reproducing head and a signal processing circuit for supplying a signal detection current and voltage to the TuMR head and amplifying and processing a signal obtained from the TuMR head. In this magnetic recording/reproducing apparatus, when the SNR of a detection signal processed in the signal processing circuit exhibits the maximum value within a predetermined range of voltages applied to the TuMR head, the TuMR head is driven by a voltage drive circuit; otherwise, the TuMR head is driven by a current drive circuit. The TuMR head is used as a mainstream reading head for a magnetic recording/reproducing apparatus regardless of whether the magnetic recording/reproducing apparatus adopts a horizontal recording mode or vertical recording mode.
However, the TuMR head is still in the early days of its development and therefore has a problem concerning long-term reliability throughout product life under today's situation that quality verification time must be shortened.